Field
Embodiments of the present invention generally relate to the field of semiconductor process chambers, and more particularly, to shutter disks for use in semiconductor process chambers.
Description of the Related Art
Conventional semiconductor device formation is commonly performed in one or more process chambers, typically combined to form a multi-chamber processing system (e.g., a cluster tool) which has the capability to process multiple substrates (e.g., semiconductor wafers) in a controlled processing environment. To maintain process uniformity and ensure optimal performance of the process chamber, various conditioning operations are periodically performed. For example, in a physical vapor deposition (PVD) processing chamber, one commonly used conditioning operation is a “burn-in” process, wherein a target disposed in the PVD processing chamber is bombarded with plasma ions to remove oxides or other contaminants from the target prior to performing substrate processes. Another commonly used conditioning operation is a “pasting” process, wherein a covering is applied over material deposited on process chamber surfaces to prevent the material from flaking off the process chamber surfaces and contaminating the substrate during subsequent processes.
In both of the aforementioned conditioning operations, a shutter disk may be positioned via a transfer robot atop a substrate support disposed in the process chamber to prevent the deposition of any materials upon the substrate support. Thus, the shape of the shutter disk is important for both the positional accuracy of robotic handling and placement, along with substrate support coverage, as errors in either may lead to undesirable exposure of the upper surface of the substrate support during the conditioning operations.
Moreover, conventional shutter disks are typically made of a material having a mechanical stiffness sufficient enough to resist deformation due to the additional weight of the deposited material. For example, the shutter disk commonly comprises a metal alloy, such as stainless steel (SST), or a ceramic, such as silicon carbide (SiC). However, shutter disks constructed of such materials weigh a substantial amount, leading to increased costs due to providing and maintaining a transfer robot capable of securely maneuvering the shutter disk. In addition, the coefficient of thermal expansion (CTE) is limited in range, resulting in a potentially significant difference between the coefficients of thermal expansion of the shutter disk and deposited materials, leading to diminished adhesion between the deposited material and the surface of the shutter disk, thus increasing the risk of the deposited material peeling or flaking off and contaminating the underlying substrate support. To alleviate this problem, the surface of the shutter disk may be textured via an abrasive blasting process to increase adhesion. However, due to the hardness of materials such as SST or SiC, such processes are difficult and costly.
Thus, there is a need for an improved shutter disk.